1. Field of the Invention
The present invention relates to an ink-jet recording apparatus for recording an image on the recording paper by discharging ink droplets from a recording head. In particular, the present invention relates to an ink-jet recording apparatus including a movable support section provided for a platen.
2. Description of the Related Art
An ink-jet recording apparatus includes a recording head in which a large number of nozzles are provided in an aligned manner. The recording paper, on which an image is to be recorded, is transported to the position under the recording head. The recording head discharges ink droplets from the nozzles at the predetermined timing while being moved in the primary or main scanning direction (direction perpendicular to the transport direction of the recording paper). Accordingly, the image is recorded on the recording paper. In recent years, the ink-jet recording apparatus is provided with the function to record an image on the recording paper, for example, as if a photograph print is produced. The image recording of this type is performed without providing any blank space or margin at the edge of the recording paper, which is referred to as so-called “borderless recording”.
When the borderless recording is performed, the recording head discharges the ink to the outside of the recording paper while exceeding the edge of the recording paper. For example, in the case of the borderless recording performed at the forward end and the backward end of the recording paper, the recording paper is positioned with respect to the recording head so that parts of the large numbers of nozzles are arranged outside the edge of the recording paper. The ink droplets are discharged from the nozzles onto the platen arranged under the recording paper. The platen is provided with a groove which is disposed at an upper portion and which extends in the main scanning direction. An ink-absorbing member is provided in the groove. Accordingly, the ink droplets are absorbed by the ink-absorbing member. Therefore, the image is recorded on the entire recording paper without forming any blank space at the edge of the recording paper, and the back surface of the recording paper is not dirtied by the ink discharged onto the platen (see, for example, U.S. Pat. No. 6,239,817 B1 corresponding to Japanese Patent Application Laid-open No. 2000-118058).
In recent years, it is demanded for the ink-jet recording apparatus to realize the high speed image recording. In order to realize the high speed image recording, it has been hitherto intended to allow the recording head to have a large size, for the following reason. That is, when the recording head is large-sized, then the number of nozzles aligned in the transport direction of the recording paper is increased, and the high speed recording can be performed. However, in order to satisfactorily perform the borderless recording as described above, it is necessary that the widthwise dimension (dimension in the transport direction of the recording paper) of the groove provided for the platen is also set to be large as the recording head is large-sized.
When the borderless recording is performed as described above, the recording paper is arranged over the groove provided for the platen. Therefore, if the groove width is large, then the recording paper is warped downwardly in the vertical direction, and the recording paper is deformed such that the recording paper falls into the groove. If the recording paper is warped as described above, then the distance is changed between the nozzle of the recording head and the surface of the recording paper, and there is such a possibility that any recording defect may arise.
In order to dissolve the inconvenience as described above, the following conventional technique is known. That is, a printing paper support member is provided in the groove of the platen, and the printing paper support member is rotated while following the transport of the recording paper. Accordingly, the printing paper support member supports the recording paper advanced to the position over the groove. The portion, which supports the recording paper, is moved in the widthwise direction of the groove. Therefore, the recording paper is supported by the printing paper support member even when the recording paper is transported over the groove of the platen (see, for example, U.S. Patent Application Publication No. US 2002/191064 A1 corresponding to Japanese Patent Application Laid-open No. 2001-80145 and U.S. Patent Application Publication No. US 2002/154203 A1 corresponding to Japanese Patent Application Laid-open No. 2002-307769).
However, the conventional printing paper support member is rotated about the center of a predetermined rotation center shaft (see U.S. Patent Application Publication No. US 2002/191064 A1). Therefore, the forward end of the printing paper support member (portion to make contact with the recording paper) approaches the recording head, and then the forward end is separated therefrom. For this reason, the printing paper is not necessarily supported in parallel to the recording head at all times. In order to solve this problem, it is appropriate that the radius of rotation of the printing paper support member is set to be sufficiently large. However, in this case, a new problem arises such that the ink-jet recording apparatus is consequently large-sized. Another technique is known, in which the surface of the printing paper support member for supporting the recording paper is formed to be circular arc-shaped about the center of the rotation center shaft. However, in this case, the point for supporting the recording paper is consequently fixed. The end of the recording paper to be transported is not supported at all times. That is, when the surface for supporting the recording paper is formed to be circular arc-shaped, then the recording paper is supported at only the support point, and the portions corresponding to those other than the support point (areas disposed frontwardly and rearwardly with respect to the support point) are consequently warped. As a result, there is such a possibility that any recording defect may arise in the same manner as described above.
The relative positional relationship between the recording paper to be transported and the nozzle, especially the distance between the recording paper and the nozzle is important in order to vividly record the image by means of the ink-jet recording apparatus. In order that the distance is maintained to be constant, it is necessary to avoid the floating of the recording paper to be transported from the platen. The cause of the floating of the recording paper is principally the initial deformation (for example, bending and curvature) of the recording paper to be transported. However, it is also considered that the cause is the cockling phenomenon of the recording paper during the recording. In order to restrict the distance between the recording paper and the nozzle to be within a constant range, it is conceived that a guide member is installed on the platen in order to suppress the floating of the recording paper.
Some ink-jet recording apparatuses, which are available in recent years, are provided with, for example, the function to record the image as if a photograph print is produced. The image recording of this type is performed without providing any blank space at the edge of the recording paper, which is referred to as so-called “borderless recording”. In contrast to the borderless recording, the recording, in which the blank space is provided, is referred to as “bordered recording”. When the bordered recording is performed, a thin paper sheet having a relatively large size, which includes, for example, the regenerated paper and the regular paper of the A4 size, is used in many cases. For this reason, the deformation of the recording paper is apt to arise during the recording. Therefore, when the bordered recording is performed, any large deformation of the recording paper is avoided by providing the guide member as described above. As a result, the recording paper does not undergo, for example, the so-called paper jam and the stain or dirt which would be otherwise brought about by the interference with the recording head, and thus the vivid bordered recording is realized.
However, when the borderless recording is performed, the recording head discharges the ink to the outside of the recording paper while exceeding the edge of the recording paper. Therefore, when the borderless recording is performed, if the guide member is arranged on the platen, then the vivid borderless recording is inhibited. That is, in order to realize the vivid bordered recording, the guide member should be arranged on the platen so that the distance between the recording paper and the recording head is maintained to be within a constant range by restricting the floating of the recording paper from the platen. However, when the borderless recording is performed, it is feared that the guide member may intercept the ink droplets discharged from the recording head toward the recording paper. In this situation, an inconvenience arises such that it is difficult to perform the vivid borderless recording. On the other hand, when the borderless recording is performed, a thick paper sheet such as the glossy paper for the photograph is generally used in many cases. The deformation of the recording paper is hardly caused during the recording. Therefore, it is considered that the necessity of the guide member is low when the borderless recording is performed.